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H. P. CLAUSEN AND C. L. GOODRUM.

MACHINE SWITCHING TELEPHONE SYSTEM.

APPLICATION FILED APR. l2. I917.

Patented June 2 1-, 1919.

UNITED STATES PATENT OFFICE.

HENRY P. CLAUSE-N, OF MOUNT VERNON, AND CHARLES L. GOO'DRUM, OF NEW YORK, N. Y., ASSIGNORS TO WESTERN ELECTRIC COMPANY, INCORPORATED, OF NEW YORK,

N. Y., A CORPORATION OF NEW YORK.

MACHINE-SWITCHING TELEPHONE SYSTEM.

Specification of Letters Patent.

Patented June 24, 1919.

To all whom it may concern:

Be it known that we, HENRY I. CLAUSEN and CHARLES L. GOODRUM, citizens of the United States, residing at Mount Vernon, in the county of \Vestchester and State of New York, and at New York, in the county of New York and State of New York, respectively, have invented certain new and useful Improvements in Machine-Switching Telephone Systems, of which the following is a full, clear, concise, and exact description.

This invention relates to machine switching telephone systems, and particularly to those systems wherein a train of automatic switching mechanisms are operated in succession.

The object of the invention is to provide means whereby the switching mechanism, ordinarily adapted to be operated only after another has completed its operation, may be started before such other has reached the final stage of its operation.

The invention is shown herein as applied to a line finder switch and an associated first selector switch, such arrangement being the preferable embodiment of the invention, but not the only arrangement contemplated.

It sometimes happens that in a system where the selector switches are directly set by the calling subscriber that the first series of impulses is sent before the line finder switch has completed its operation, in which case the first selector is wrongly set, not having received the full set of impulses.

This invention aims to overcome such difficulty by means which allow the impulses to reach and affect the first selector switch after the line finder has started, but before it has found the calling line.

Specifically, the invention contemplates the combination with a line finder switch of means for communicating impulses in a telephone line which has started such line finder switch in action to a selector switch associated therewith.

The invention, as illustrated in the draw ing, comprises a telephone system including a calling line and a line finder switch dia grammatically shown at the left of the broken line, and a first selector switch, an indicated connector switch, and a called line dia rammatically shown to the right of the bro en line.

The line finder switch and first selector switch, diagrammatically illustrated, may be of the type shown in the patent to F orsberg, No. 1,252,420, granted January 8, 1918.

A clear understanding of the invention may be had from the following description of the operation of a system embodying this invention.

Let it be assumed that the subscriber at substation A removes the receiver from its hook. A circuit is thereupon established from the battery, the left-hand winding of relay LR, left-hand armature and contact of relay CO, upper limb of the telephone line 1, through the apparatus of the substation A, lower limb of the telephone line 2. contact and right-hand armature of relay CO, right-hand winding of relay LR, to ground. Relay LR is energized and by attracting its armature establishes a circuit from ground, right-hand armature and contact of relay LR, the winding of slow-release relay GR, to battery and ground. Current flowing through this circuit energizes the relay GR, which in turn actuates its armatures and establishes a circuit from ground, the outer right-hand armature and contact of relay GR, side switch wi or IV, contact and armature of relay to battery and ground. The rela PM upon attracting its armature breaks tie circuit just described and upon retracting its armature again establishes the circuit. In this manner the armature is caused to vibrate until the relay PM is permanently energized in a manner to be described.

The actuation of the outer righthand armature of the relay GR also establishes a circuit from dground, the outer ri ht-hand armature an contact of relay B, sideswitch wiper W and its first position contact, and the windin of relay 3, to battery and ground. The re ay 3 attracts its armature and opens a circuit for the release magnet which will also be described.

The actuation of the relay LR places a ground on the terminal 4 of commutator C, traceable from ground, right-hand armature and contact of relay LR, to terminal 4. The arm 5 being keyed to the shaft of the switch revolves with it until it comes in contact with a grounded terminal 4. At this time the ground on terminal 4 is projected through the arm 5, side switch wipers Vi. W and their first position contacts, the Winding of escape magnet E, the windin of magnet PM, to battery and ground. l he magnet PM permanently attracts its armature and the movement of the arm 5 ceases. Magnet E attracts its armature and in the wellhnown manner moves the side-switch wipers into their second position.

A circuit is now established from ground, right-hand arnniture and contact of relay Llt, terminal 4-, arm 5, side-switch wiper W and its second position contact, side-switch wiper W and its first position contact, the left-hand winding of relay LR, to battery and ground. Relay LR is energized and ate tracts its armature.

A circuit is also established from ground, the outer right-hand armature and contact of relay GR, side-switch wiper W and its second position contact, armature and contact of relay SM, the winding of relay SM, to battery and ground. Relay SM, by breale ing its own circuit, sets up a ibratory action, and moves the brushes B, It and 1% step by step over the tern'iinals T, T and T As the brushes B, B and B traverse the terminals T, T and T a circuit is estab lished from battery, the winding of cut-otl relay CO, the terminal T of other lines in the same group, brush B, side-switch wiper and its second position contact, the winding of relay TR, to ground, but the cur rent flowing thereovcr is not great enough to cause the cnergization of either of these relays. \Vheu, however, the brush B encounters the terminal T of the calling line then a circuit will be established from ground, battery, the resistance R, inner right-hand armature and contact of relay GR, contact. and lefthand armature of relay LR, terminal T and thence over the circuit previously traced. The resistance B, being somewhat smaller in value than the resistance of the cut-off relay CO, enough current will now flow over this circuit to energize the relay TR.

\Vhen the sidc-switch wiper W moved into the second position, the circuit from round, the contact and armature of relay R, the second position contact of side-sw1tch wiper W, the winding of magnet E, the winding of magnet PM, to battery and ground, established, whereby these rela s were main tained in their energized con ition. Upon the energization of the relay TR this circuit is broken at the armature and contact of relay TR and the magnet E becomin denergized causes the movement of the si e-switch wipers into their third position, which re sults in the opening of the circuit for the magnet SM and the stopping of the brushes B, B and B on the terminals of the calling line.

In the third position, a circuit is established from ground, third position contact and sideswitch wiperVV, brush B, terminal T, the winding of cut-ol'l' relay ()0, to battery and ground. Relay ()0 now be comes sullicicntly energized to attract its arniaitures, whereupon the energizing circuit for the relay LR is broken, and this relay retracts its armatures. In turn, the relay Glt is deenergized and it. retracts its arma tures.

\Vhen the side-switch wipers W" and W'" more into the third Josition the calling tele" phone line is extem ed to the first selector switch, whereby the relay LR is maintained energized over a new circuit traceable from ground, battery, left-hand winding of relay LR, first position contact and side-switch wiper i the third position contact and side switch wiper W, the brush B the terniinal T, lower limb of the telephone line 2, the apparatus of the substation A, the upper limb of the telephone line 1, the terminal T, the brush B the sideswitch wiper W" and its third position contact, sideswitch Wiper and its first position contact, right-hand armature of relay lilt, to ground. The en ergization of relay LR causes the energize. tion of the first slow relay FS over a circuit traceable from ground, the armature and alternate contact of the relay LR, winding of relay FS, to battery and ground. The first selector switch is noW in condition to receive impulses caused by the intermittent breaking of the line circuit by the actuation of the sender D.

Assuming that the subscriber now actuates this sender, the relay LR will cause its armature to vibrate in the well-known manner. Upon the first retraction of its armature a circuit is established from ground, the armature and norn'ial contact of relay LR, the armature and alternate contact of relay FS, to a point where the circuit divides, extending in one direction throu h the Winding of the second slow relay S to battery and ground, and in the other direction through the sideswitch Wiper W and its first position contact, the winding of primary magnet PM, to battery and ground. Upon the attraction of its armature by the relay LR the magnet PM becomes denergiZed but the relay SS, being slow to release does not retract its armature for an appreciable time thereafter. If there be more than one break in the line caused by the operation of the sender D, then the magnet PM will be energized in synchronism with each such break and the brushes B, B and B will be rotated in position before the group containing the terminals T, T and T.

The energization of the second slow relay SS results in the establishment of a circuit from ground, the armature and contact of relay SS, the winding of magnet E to battery and ground. At the end of the first series of impulses, the relay SS is given time to deenergize, and upon retracting its armature breaks the circuit for the energization of magnet E and allows the sideswitch wipers of this first selector switch to be moved into their second position. As the side-switch wiper W moves into its second position, a circuit is established from ground, armature and alternate contact of relay LR, the side-switch wiper W and its second position contact, the armature and contact of relay SM, to battery and ground. The rela SM by attracting its armature opens t is circuit iand: thereby causes a vibratory action which drives the brushes B, B and B over the terminals T, T and T until the brush B encounters the terminal T of an idle trunk, which is characterized in the well-known manner by a ground potential. Thereupon round will be projected from the terminal 4 over the brush B, the second position contact and side-switch wiper W, the winding of magnet E to battery and ground, and the magnet E will be energized, thereby escaping the side switch wipers into their third position.

The movement of the side-switch wipers W and W into their third position results in the seizure of the trunk leading to the connector switch CS, whereupon the ground projected to the terminal T is removed and the trunk characterized, by the absence of this ground, as busy.

In the well-known manner, the connector switch CS is driven into association with the line leading to the subscriber B, and other operations necessary to the establishment of the connection performed.

Assuming that the called subscriber answers and that after a period of conversation he replaces the receiver on its hook. This action results in the placing of ground on terminal T whereupon such ground is projected over the brush B, through the side-switch wiper W and its third position contact to a point where the circuit divides, extending in one direction through the offnormal contact ON the winding of the release magnet R to battery and ground, and in the other direction through the armature and contact of relay 3, which became denergized when the side-switch wiper W moved into the third position, the ofl-normal contact ON, the winding of release magnet R, to battery and ground. Both of these release magnets attract their armatures and establish holding circuits for themselves from ground, the contact and armature of relay R in the one case, and ground, the contact and armature of relay R in-the other case. These relays are then held energized until the respective switches are fully released, whereupon the opening of the off-normal contacts breaks their holding circuits.

Assume that the line finder switch has reached the stage in its operation where the arm 5 has made contact with the terminal, and the side-switch wipers W and W 4 have been moved into their second position. Assume also that the subscriber at substation A manipulates his dial switch an instant later. During the following movement of the shaft, in response to the actuation of the secondary magnet, the arm 5 remains in contact with the terminal being keyed to the shaft for this purpose. The relay LE which has just been energized over the circuit previously traced through the second position contact and side-switch wiper W' etc., will now be deenergized through the retraction of its armatures by the relay LR, directly controlled by the subscribens substation apparatus. The impulses'sent will cause the armature of relay LR to vibrate and such vibration will be communicated over the circuit previously traced, and in the manner previously described, to the relay LE causing it to vibrate its armature in synchronism. The action described in connection with the first selector switch will now take place exactly as before with the exception that the energization of the relay LR is caused by a circuit extending through its left-hand winding only. If, before the train of impulses being sent by the subscriber is completed, the line finder switch completes its operation and the cut-ofl relay CO is thereby energized, the side-switch wipers W and VV will extend the calling line to the relay LE and it will continue in its vibration now under control of the circuit through which both its right and left-hand windings are energized. The action thereafter is as previously described.

What is claimed is:

1. In a telephone system, a telephone line, a two-movement non-numerical switching mechanism, a numerical switching mechanism, and means included in said nonnumerical mechanism operable upon the completion of its first movement for bringing said numerical switching mechanism under the control of said line.

2. In a telephone system, telephone lines, automatic switching mechanisms for eX-a tending said telephone lines, directively controlled switching mechanisms for further extending said telephone lines, means included in said automatic switching mechanisms operable before said automatic switching mechanisms have completed their selecting operation for bringing said directivcly controlled switchin mechanisms under the control of said te ephone lines.

3. In a telephone system, telephone lines, switching mechanisms arranged to be directively controlled by said telephone lines, automatic switching mechanisms for extending said telephone lines to said dircctivcly controlled switching mechanisn'is, and means included in said automatic switching mechanisms operable before said automatic switching mechanisms have completed their selecting operation for bringing said direclivcly controlled switching mechanisms under control of said lines.

4-. In a telephone system, a non-numerical switching mechanism, a numerical switching mechanism, and means included in said non-numerical switching mechanism for starting said numerical switching mechanism prior to the completion of the selecting operation of said non-numerical switching mechanism.

5. In a telephone system, a non-mnnerical selector, a numerical switching mechanism, and means included in said nonnumcrical selector operable before said hon-immerical selector has completed its selecting operation for starting said numerical switching mechanism.

6. 111 a telephone system, selector switches arranged for successive operation, and means included in one for actuating another before the one has completed its selecting operation.

7. 1n a telephone system, telephone lines, selector switches, means including said selector switches for interconnecting said lines, said switches being arranged for successive operation, and means included in the first of said switches to be actuated for starting the second of said switches before the said first of said switches has completed its function.

8. In a telephone system, a t\v'()-lll0"l, ment non-numerical switching mechanism, a numerical switching mechanism, and means included in said non-numerical mechanism,

operable upon the completion of its first movement for starting said numerical switching mechanism.

9. In a telephone system, a telephone line, a non-nnmcrical switching mechanism for extending said line, a numerical switching mechanism for further extending said line, and means included in said non-numerical switching mechanism for bringing said numerical switching mechanism under control of said line before said non-numerical switching mechanism has extended said line to said numerical switching mechanism.

10. In a telephone system, a telephone line, a non-numerical selector, a numerical selector, and means included in said. nonnumerieal selector operable before said nonnumerical selector has completed its select ing opcratioi'i for placing said numerical selector under the control of said line.

11.. In a telephone system, a telephone line, selector switches arranged for successive operation, and means included in one for bringing the other under the control of said line before the one has completed its selecting operation.

12. In a telephone system, telephone lines, selector switches, means including said selecting switches for interconnecting said lines, said switches being arranged for successive operation, and means included in the first of said switches to be actuated for bringing the second of said switches under the control of said lines, before the said first of said switches has completed its function. I

In witness whereof we hereunto subscribe our names this 11th day of April, A. 1

HENRY P. CLAUSEN. CHARLES L. GO'ODRUM.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. 0." 

